1. Field of the Invention
The present invention relates to a composition for relieving atopic dermatitis containing natural extracts.
2. Discussion of Related Art
The epidermis, which is the outer layer of the two main layers that make up the skin, protects the human body from the outside. The stratum corneum, which is the outermost layer of the epidermis, acts as a barrier, inhibiting moisture evaporation or loss from the epidermis (preventing drying), and also preventing bacteria, fungi, viruses, and the like from penetrating the skin. The stratum corneum is composed of two components, corneocytes (terminally differentiated keratinocytes) and lipid-enriched lamellar membrane structures. The architecture of the stratum corneum is referred to as “bricks (corneocytes) and mortar (lamellar membranes)”. Several layers of corneocytes are present in the stratum corneum.
Atopic dermatitis is a skin disorder with symptoms such as strong pruritus with unclear causes, dryness, severe keratinization, scalp squama (dandruff), erythema and turgidity, skin crack, severe oozing and eczema, lichenification, and the like. Atopic dermatitis is generally considered to be a chronic disease, lasting more than 10 years and causing great discomfort. Previously, in most cases, after atopic dermatitis occurred in infancy or early childhood, the symptoms gradually disappeared before the age of 7 to 8 years.
However, since the 1970s, the incidence of atopic dermatitis has increased year by year due to pollution caused by rapid industrialization, environmental pollution, and the like. Symptoms of atopic dermatitis that emerges during childhood tend to persist until adolescence and adulthood and gradually worsen. In addition, the incidence of atopic dermatitis after adolescence has also increased remarkably. The main symptom of atopic dermatitis is skin inflammation with strong pruritus, and the main cause of pruritus is histamine hypersecretion. Scratching the skin due to pruritus may lead to erythema or eczema lesions, and in severe cases, the skin may peel off or lichenification (thickening of the skin) may occur.
Until recently, research results and information about the causes of atopic dermatitis have been reported. However, the reported research data are contradictory, which may be due to the complexity of atopic dermatitis itself. Therefore, clear causes and effective treatment methods for atopic dermatitis have not yet been clearly established.
Due to these problems, therapeutic agents that alleviate symptoms to some extent, rather than fundamental treatment, have been used to treat atopic dermatitis. Examples of the therapeutic agents include steroid preparations, oral antihistamines, hydroxyquinoline, tar preparations, and hypoallergenic moisturizers. However, none of the medicines developed so far can completely treat patients with atopic dermatitis.
Meanwhile, cosmetics for relieving atopic dermatitis should basically not cause pruritus and skin irritation, and should have functions such as a skin soothing effect, inflammation inhibition, bacterial growth suppression, moisturization, and skin barrier maintenance.
However, research has shown that chemical preservatives (e.g., parabens, phenoxyethanol, and diazolidinyl urea) used in cosmetics for relieving atopic dermatitis developed so far cause DNA damage. In addition, these preservatives have been reported to exacerbate the symptoms of atopic dermatitis.
Thus, to reduce side effects such as skin irritation, there is increasing demand for cosmetics containing natural ingredients, with a minimal amount of chemical ingredients. Accordingly, research is actively being carried out to develop cosmetics for relieving atopic dermatitis having excellent in vivo biostability and an excellent skin soothing effect.